In the Tengwar system of writing, the Tyeller were the six "grades" used to indicate modifications to a basic sound in Tengwar and represented six modes of articulation in the mouth.
The Tyeller were signified by the length of the telco and the number of the luvar (one or two). Some specialized Tengwar modes had eight tyeller instead of six, containing an extended telco both above and below the line.
For example, where the first tyellë referred to the basic patakar, the tengwar known as Tinco, Parma, Calma and Quesse, the following tyeller would typically represent modifications of their basic sounds.
It is also one of the few words ending in -e which forms the plural in -r, instead of -i, hence tyeller instead of **tyelli.